The present invention relates to a support system for conduit and the like and more particularly to seismic bracing employed for effectively resisting relative movement in any direction between the conduit and a structural surface or element.
Various support or hanger systems are commonly employed for mounting pipe, conduit, light fixtures and other types of similar equipment and other structures with spaced apart portions of the conduits being supported from anchors or channels secured to a structural surface such as a ceiling or wall of a building. The support or hangers may engage single conduits or they may be adapted in the manner of so called "trapeze" hangers to provide support for a number of parallel conduits.
Regardless of the specific type of hanger system and conduit arrangement, it is becoming increasingly important to anchor the conduits in order to prevent relative movement between the conduit and the structure from which it is suspended. Generally, supports or hangers of the type referred to above extend vertically between the conduit and a structural surface in order to carry the weight of the conduit. However, in the event of external forces such as seismic conditions, the conduits may tend to experience relative movement, for example either laterally or axially in relation to its axis.
Various code requirements for buildings and the like, at least in certain geographical areas require that such relative movement be limited or constrained in order to prevent rupture or discontinuity within the conduits.
The limiting of relative movement between conduits and structural support is known in the prior art and generally comprises the use of braces for interconnecting the suspended conduit with an anchor point which is in turn secured to the support structure for the conduit. However, a number of problems have been observed in connection with such seismic bracing systems employed in the prior art. Initially, the systems commonly include braces which extend radially outwardly and vertically upwardly from the axis of the conduit toward an anchor point. Braces of this type thus extend perpendicularly from the conduit and permit the use of relatively simple brackets for interconnection. However, the use of such braces tends to limit movement of the conduit only in one or two directions. For example, a brace of the type referred to immediately above tends to limit both vertical and lateral movement of the conduit relative to its axis. However, such a brace does not effectively limit or restrain relative movement of the conduit along its axis.
Further, if such a seismic bracing system is to be effective, it is necessary to resist very substantial bending forces tending to act upon the braces because of the relative movement between the anchor point and the conduit. Prior art bracing systems have not been found to adequately anticipate or to make provision for overcoming the effects of such bending forces.
Accordingly, there has been found to remain a need for an effective seismic bracing system where relative movement in any direction between the suspended conduit and a structural surface or element is effectively limited or restrained.